Air conditioning



April 9, 1940. c. Emol-:GER 2,196,473

AIR CONDITIFONING Filed Dec. 17, 1935 ATTORNEY.

Patented Apr. 9, 1940- UNITED STATES AIR CONDITIONING Clyde E. Ploeger, Evansville, Ind., assignor to v' Servel, Inc., New York, N. Y., a corporation of Delaware Application December 17, 1935, Serial No. 54,828

fs claim.- (c1. 62.6)

My invention relates to air conditioning and more particularly to a ventilation system in which air is dehumidied by cooling with refrigeration apparatus.

Ina system of this type, air to be conditioned may be cooled to a temperature below its dew point to cause condensation of water vapor and' thereby reduce the absolute humidity of the air. This cooling may be effected by flowing air in thermal transfer relation with the cooling element of a refrigeration apparatus. The resulting cold dry air is then at a temperature too low for comfort so that if the system is employed for comfort cooling it is preferable to increase the dry bulb temperature of the air before introduction into an enclosure to be conditioned. This heating may be accomplished by flowing the air in thermal transfer relation with the condenser or a portion of the condenser of the refrigeration apparatus.

In accordance with my invention I provide improved means for accomplishing cooling of air for dehumidification and subsequent re-heating, and also provide for simplified control of the air temperature. I provide a heat exchanger such as vaporization-condensation member containing a volatile fluid, which is arranged so that the vaporization portion of the member is in thermal exchange relation with the air before the air is cooled by the cooling element of a refrigeration apparatus and so that the condensation portion is in heat exchange relation with the air after it has been cooled and dried. Heat absorbed by the vaporization portion in precooling of the air 85 is returned to the air after it has been dried. The vaporization portion is arranged below the condensation portion so that the heat transfer uid circulates automatically therein, that is, the vaporous ,fluid liquees in the condensation por- 4o tion and returns by gravity to the vaporization portion. I further arrange a portion of the condenser of a refrigeration apparatus in the air stream and provide for controlling the cooling of the other portion of the condenser responsive to 45 temperature of the air which is to be maintained substantially constant at a predetermined temperature.

For a better understanding of my invention reference may be had to the following descrip- 60 tion taken in connection with the accompanying drawing in which Fig. 1 more or less diagramserves as a duct through which air is circulated. The lower portions of the walls of the casing are grilled to provide an inlet, as indicated at II, and the upper end is provided with a discharge a opening adjacent which is disposed a vfan I2 5 driven by a motor I 3 supported within the casing. The fan I2 withdraws air from an enclosure through the grilles II, draws the air upwardly through the casing past cooling and reheating elements whereby the air is conditioned, and 10 delivers the conditioned air to the enclosure through the discharge opening, the path of flow of air just described being indicated by the arrows in Fig. 1.

As air is drawn upwardly through the casing l5 III, it ows over the surfaces of a cooling element comprising a zig-zag coil I4 having cross plates or fins I5 which are xed to the coil in close spaced relation. The coil I4 is arranged substantially horizontally within the casing III, and 20 a. relatively large dsurface is presented by the finsA I5 to withdrawn air for cooling anddehumidifying the air. The moisture condensed from the air when it is cooled below its dew point drips from the surfac'es of the coil I4 and plates I5, and is 25' collected at the bottom of the casing from which it flows through a drain pipe I 6 which may have a suitable connection for carrying away the water.

After being cooled and dehumidifled, the air 30 ows over the surfaces of a reheating element constructed in the same manner as the cooling element just described and comprising a zig-zag coil I1 having plates or ns I8 fixed thereto, whereby a relatively large heat dissipating surface is provided to add sensible heat to the cooled air before it is delivered to the enclosure.

The zig-zag coils I4 and I'I of the cooling and reheating elements form the evaporator and condenser, respectively, of a refrigerating system. This refrigerating system may comprise a motor and-a compressor driven thereby which coinpresses the refrigerant gas. During operation, the compressed refrigerant gas is discharged from the compressor and flows through a water cooled condenser comprising a conduit I9 provided with a jacket 20- having inlet and outlet connections 2l and 22,-respectively, through which` cooling water can be circulated.

All or a part of the condensation of the compressed refrigerant gas may be effectedin the water cooled condenser, as willbe described hereinafter, and the condensed or partially condensed refrigerant ows therefrom through the condenser coil I1 which may, with the plates I8, serve 35 as a reheating element to reheat the cooled and dehumidifled air which flows over its surfaces, as previously mentioned. In this manner, heat abstracted from withdrawn air by the evaporator coil I4 may, if desired, be restored to the cooled air.

The refrigerant, which is condensed either in the water cooled condenser or both in the water cooled condenser and condenser coil I1, flows through a pipe 23 and, under the control of an expansion valve 24, into the evaporator coil I4. The vaporized refrigerant is withdrawn through pipe 25 from the evaporator coil I4 by the compressor, in which it is again compressed and the refrlgerating cycle repeated. l

In accordance with my invention, in order to reduce the amount of work that must be done by the refrigerating system to cool and dehumidify withdrawn air, a vaporization condensation member is provided which contains a volatile uid that serves as a heat transfer agent. This member comprises avaporization portion which is in the form of a zig-zag coll 26 supported within the casing Ill below the evaporator gcoil I4, and a condensation'portion which is in the form of a zig-zag coil 21 supported Vwithin the casing between the evaporator coil I4 and condenser coil I1, the ends of the coils 26 and 21 being connected by vertical pipes 28 and 29 to provide a closed iluid system. To the coils 26 and 21 are fixed a plurality of plates 30 and 3l, respectively, in a manner similar to that shown in Fig. 2, so that relatively large surfaces are presented to withdrawn air as it ows upwardly through the casing I0.

The volatile liquid vaporizes in the coil 26, abstracting sensible heat from withdrawn air to supply the heat of vaporization, and the vapor of the volatile liuld flows upwardly to the coil 21 from which abstracted heat is returned to dehumidified air. In transferring heat to dehumidied air, the vapor is condensed to liquid state, and., since the coil 21 is disposed above the coil 26, the condensed liquid flows by gravity back t0 the coil 26. liquid serves as a heat transfer agent which circulates naturally through the closed fluid system. The coils 26 and 21 are preferably supported in an inclined position, as shown in Fig. 1, so that the vaporized heat transfer agent will flow upwardly through pipe 28, and the condensate'will flow downwardly through pipe 29.

In order vto dehumidify withdrawn air it is necessary to reduce the temperature of the air from the dry bulb temperature below the dew point. When sensible heat is abstracted from withdrawn air` by flowing over the surfaces of the coil 26 and plates 30, the dry bulb temperature of the air is lowered considerably, kso that the quantity of refrigeration that must be effected by the evaporator coil I4 to bring withdrawn air below the dew point is reduced a substantial amount. Since the pre-cooling of withdrawn air is accomplished automatically without any me' rlating the amount of reheating that will be eifected by the condenser coil I1 when air flows over the surfaces of this coil and the plates I8.

It will therefore be seen that the volatile This is accomplished by positioning a thermostat 32 within the casing I0 adjacent the discharge opening, and connecting such thermostat by a capillary tube 33 to a thermostatic water control valve 34 which is located in the inlet connectio'n 2| of the water cooled condenser. The thermostat 32 and capillary tube 33 are lled with a suitable fluid, and constitute an expansible fluid thermostat for controlling the valve 34 to increase the amount of water circulated through the condenser when the air delivered to the enclosure is above a desired temperature; and, conversely, to decrease the amount of watercirculated through the condenser when the air l delivered to the enclosure is below the desired temperature.

When the amount of water circulated through the condenser is increased, more condensation of compressed refrigerant gas takes place in the water cooled condenser, so that less reheating can be effected through the condensation of refrigerant gas in the condenser coil I1 andthe temperature of conditioned air is reduced to the desired temperature; and, when the amount of Water circulated through the water cooled condenser is decreased, less condensation of refrigerant gas takes place in the water cooled-con denser, so that a greater amount of reheating can be effected through the condensation of refrigerant gas in the condenser coil I1-'and the temperature of conditioned' air is increased to the desired temperature. It will therefore be seen that the desired temperature of conditioned air delivered to the enclosure can be readily controlled by' adjusting the valve 34 in the inlet water connection 2I. Although I have fully describedreheating of the air by heat of the condenser portion I1 and the coil 21 of the Vaporization-condensation member, any suitable heat exchanger may be provided in place of the vaporization-condensation member.

It will be understood that `various changes and modifications may be made within the scope of the invention indicated by the following claims.

What is claimed is:

1. A ventilation system including an enclosure, a duct, means for flowing air through said duct to the enclosure, refrigeration apparatus including a cooling element and a condenser for respectively dehumidifying and partially reheating air flowing through said duct, said cooling element and a portion of said condenser being positioned in spaced relation in said duct, means including a heat conducting fluid circuit for precooling air prior to dehumiditlcation and for partially reheating dehumidied air, said circuit.

having a heat absorbing part positioned in said duct ahead of said `cooling element relative to the ilow of air and a heat dissipating part positi'oned in said duct between said cooling element and said portion of the condenser, and means responsive to the temperature of the air delivered fromvsaid duct for controlling cooling of the other portion of said condenser.

2. Air conditioning apparatus comprising a casing through which air may ilow upwardly and having an inlet and an outlet above the inlet, means for circulating air upwardly through said casing, means including an evaporator element and a condenser of a refrigerating system for dehumidifying and for subsequently partially reheating air flowing through said casing, said evaporator element and a portion of said condenser being positioned in spaced relation in said casing, said evaporator element being 4disposed be- 75 sponsive to the temperature of air discharged from the outlet for controlling said last-mentioned means.

3. An air conditioning system including means providing a passage for air to be conditioned, refrigeration apparatus including a cooling element and a condenser, said cooling element and a portion of said condenser being positioned in spaced relation in the passage for respectively dehumidifying and reheating air flowing therein,v

and means operative responsive to a temperature condition of the dehumidified and reheated air to control cooling of the other portion `of said l0 condenser. t

' CLYDE E. PLOEGER. 

